Elimination of cationic dyeability of acrylic fibers



United States Patent 3,222,118 ELIMINATION OF CATIONIC DYEABILITY F ACRYLIC FIBERS Denis Coleman, Stamford, Conn., assignor to American Cyanamid Company, New York, N.Y., a corporation of Maine No Drawing. Filed May 21, 1962, Ser. No. 196,501 18 Claims. (Cl. 8115.5)

This invention relates to modification of the dyeability of acrylic fibers. More particularly, this invention relates to treating fibers of acrylonitrile containing polymerized therewith a vinylpyridine to render such fibers substantially non-dyeable by cationic or basic dyes. This invention also relates to the products of such treatment.

It is known to prepare fibers from various polymers of acrylonitrile with other substances. Particularly, it is known to polymerize acrylonitrile with various vinylpyridines so as to impart to the fibers produced therefrom the property of being readily dyeable by cationic dyes.

It is also known to prepare fabrics of a plurality of fibers having differing dye characteristics so as to produce interesting and unusual effects by the differential dyeing of such fabrics. Usually such fabrics comprise a plurality of fibers of differing chemical composition which, therefore, have differing physical properties making for difficulties in the processing and handling of such fabrics after they leave the original manufacturer. For example, differential shrinkage of the different threads made of such differing fibers incorporated into such fabrics can produce a creping or puckering of the fabrics. To avoid such difficulties, it would be desirable to have different threads made of fibers of two types having differing dye characteristics but having other physical properties as similar as possible.

In order to achieve such a highly desirable and useful result, this invention proposes modifying fibers made of acrylonitrile copolymerized with a vinylpyridine so as to greatly modify its dye characteristics in order to make it possible to produce a fabric containing both modified fibers and unmodified fibers of this type for the crossdyeing effects producible therewith.

Accordingly, it is an object of this invention to produce fibers of acrylonitrile polymerized with a vinylpyridine and treated so as to render them resistant to dyeing by cationic dyes.

It is another object of this invention to provide a method for producing such fibers.

It is yet another object of this invention to produce a fabric containing fibers made from acrylonitrile polymerized with a vinylpyridine and treated to render them resistant to cationic dyes and also containing other fibers of acrylonitrile polymerized with vinylpyridine which are not so treated and are readily dyeable by cationic dyes.

These objects, and other objects and advantages as will hereinafter appear, are mainly achieved by treating such polymers of acrylonitrile polymerized with a vinylpyridine with a bromoalkylor iodoalkylphosphate and subsequently heat-treating these fibers at a temperature of about 70 to 140 C. for one minute to ten hours prior to a subsequent step of dyeing.

For a greater understanding of this invention, reference may be had to the following examples illustrative of specific embodiments of this invention. It is to be noted that the following examples are given by way of illustration only and not by way of limitation. All parts and percentages are by weight.

Example 1 Ten parts of fibers of a polymer containing about 88% acrylonitrile, about 6.4% Z-methyl-S-vinylpyridine, and

about 5.6% vinylacetate, prepared by wet spinning such polymer from a sodium thiocyanate solution thereof as described in Cresswell US. Patent 2,558,730 and Cresswell et al. US. Patent 2,777,751, were immersed in 400 parts of water containing 8 parts of Sevron Blue 2G (Basic Blue 22), 40 parts of urea and 4 parts of sodium acetate. The solution was maintained at C. for one hour and the fiber then removed and given a light scour. The fiber was dyed a deep blue.

The above example shows the cationic dyeability of unmodified acrylic fibers containing a vinylpyridine copolymerized with the acrylonitrile therein.

Example 2 117 parts of a polymer containing about 88% arcylonitrile, about 6.4% 2-methyl-5-vinylpyridine, and about 5.6% vinyl acetate moistened with 22 parts of water were dissolved in 833 parts of a 57% aqueous thiocyanate solution.

Five parts of tris(2,3-dibromopropyl) phosphate were added to the resulting 950 parts of a 10% solution of the polymer and the mixture was stirred for 2 hours. After deaeration and filtration, the resulting solution was spun into fibers by a conventional process, such as is described in Cresswell et al. US. Patent 2,777,751, for example, which process included a step of drying the fibers for 20 minutes at C. The thusly-produced fibers were dyed using the dye of Example 1. The fiber would take up only a negligible amount of the cationic dye.

Example 3 The process of Example 2 was followed except that the dried fiber was steamed for 20 minutes at 120 C. prior to dyeing. After removing the fiber from the dye bath and giving the fiber a light scour, it was found that the cationic dyeability was completely eliminated.

Example 4 Twenty parts of a skein of acrylic fiber (containing 7.0% of Z-methyl-S-vinylpyridine copolymerized with acrylonitrile) was immersed in 400 parts of boiling wafor containing 3 parts of bis-(B-bromoethyl)-,B-chloroethyl phosphate for 15 minutes, after which the skein was removed, washed in cold water, and dried in an air oven for 8 hours at 65 C. After subjecting this skein to the dyeing procedure of Example 1, the skein was found to be undyed.

Example 5 An aqueous emulsion made up of 0.2% tris(2,3-dibromopropyl) phosphate, 0.3% xylene, and 0.04% Triton X-151 detergent (nonyl-phenyl-polyether alcohol), was heated to 75 C. and a skein of yarn of the polymer of Example 1 was immersed therein for 5 minutes. This skein was then removed, squeezed free from adhering liquor, and dried in an air oven for 30 minutes at 120 C. The thusly-treated yarn, containing 3.2% phosphate, was found to be non-dyeable by the dye procedure of Example 1.

Example 6 The process of Example 5 was repeated utilizing tris- (2,3-dichloropropyl) phosphate in the emulsion instead of the corresponding bromo compound previously used. The treated yarn, containing 3.5% phosphate, dyed normally (to a deep blue) by the dyeing procedure of Example 1.

Example 7 Another skein of the same yarn was immersed in a 5% solution of tri-iodoethyl phosphate in acetone, squeezed between rolls to remove excess liquid, and dried for 20 minutes at 115 C. The treated yarn, containing 2.5%

Example 8 The procedure of Example 7 was repeated using a solution of tris(2,3-dibromopropyl) phosphate in acetone as the treating medium. After squeezing out excess liquor and drying the treated yarn for 15 minutes at 130 C., the fiber, containing 1.4% phosphate, could not be dyed by the procedure of Example 1.

Example 9 Ten parts of a skein of the same yarn was immersed for 10 minutes in 400 parts of 0.2% of a tris(2,3-dibromopropyl) phosphate suspension in water at 85 C. To the suspension was then added 8 parts of Sevron Blue 2G, 40 parts of urea, and 4 parts of sodium acetate. The solution (suspension) was maintained at 95 C. for one hour, after which the skein was removed and given alight scour. The dye uptake was about half of that of the treated fiber of Example 1, indicating that for complete elimination of cationic dyeability it is necessary to heattreat the fiber prior to dyeing.

Example 10 A polymer containing about 88% acrylonitrile, about 6.4% 2-methyl-5-vinylpyridine, and about 5.6% vinyl acetate was spun into fibers by a process similar to that of Cresswell et al. U.S. Patent 2,777,751. After stretching the freshly formed wet gel structure in a hot aqueous bath, the wet gel was passed through a trough containing an aqueous emulsion of 5.0% tris(2,3-dibromopropyl) phosphate with 1.0% Triton X-151 (nonyl-phenylpolyether alcohol). After heating for 20 minutes at 115 C. to dry the treated yarn and steaming for 5 minutes at 120 C., the resulting fibers were found to contain 3.2% of the phosphate. This product was not dyeable by the dye procedure of Example 1.

Example 11 Ten parts of the skein of yarn treated with tris(2,3- dibromopropyl) phosphate in accordance wit-h the procedure of Example 5, but containing only 1.25% phosphate in the fiber, were immersed in 800 parts of a dye bath with ten parts of a second skein of unmodified fibers. The dye bath containing 0.5% Sevron Brilliant Red 4G (Basic Red 14) and 0.5% sodium acetate with the two skeins therein was boiled for one hour and then cooled to 160 F. Sulfuric acid was added to bring the concentration to 2% sulfuric acid, and an acid dye, 1% Calcocid Alizarin Blue AR (Color Index No. 62130) was added. The dye solution was brought back to the boil, and maintained at the boil for 30 minutes. A further quantity of sulfuric acid was added to bring the concentration up to 4.0% sulfuric acid and the solution was boiled for an additional 30 minutes. The two skeins were then removed from the dye bath and were rinsed. The treated skein was a deep blue and the untreated skein was purple, showing that the untreated skein absorbed both the acid and the basic dyes whereas the treated skein absorbed only the acid dye.

Instead of the copolymers of acrylonitrile with a vinylpyridine referred to in the above illustrative examples, there can be used for the purposes of this invention copolymers of:

95% acrylonitrile and 5% 2-vinylpyridine 92% acrylonitrile and 8% 2-methyl-5-vinylpyridine 95% acrylonitrile and 5% 2-vinyl-5-ethylpyridine 85% acrylonitrile, 7.5% methyl acrylate and 7.5% 2- vinylpyridine 84% acrylonitrile, 8% acrylamide and 8% 2-methyl-5- vinylpyridine 90% acrylonitrile, 5% hydroxyethyl methacrylate and 5% 2-methyl-5-vinylpyridine 4.- 86% acrylonitrile, 7% allyl alcohol and 7% 2-vinyl-2- ethylpyridine (or 7% 2-methyl-5-vinylpyridine) The preferred filament-forming acrylonitrile polymers that are used in making filaments, which subsequently are treated in accordance with the present invention, are those containing, by weight, at least 70% of acrylonitrile while the remainder is monoethylenically unsaturated substance including a vinylpyridine combined in a polymer molecule, and especially those containing by weight, at least acrylonitrile and at least 2% of a vinylpyridine (preferably a methyl vinylpyridine including 2-methyl-5- vinylpyridine). A preferred sub-class within this broader class is that comprised of filament-forming copolymers of, by weight, from 80% to 96% acrylonitrile, from 2% to 10% of a vinylpyridine (and which preferably includes 2-methyl-5-vinylpyridine) and from 2% to 10% of a third different monoethylenically unsaturated material, e.g., vinyl esters including the formate, acetate, propionate; the various acrylic esters including the lower alkyl acrylates and methacrylates such as the methyl, ethyl and propyl acrylates and methacrylates; the various acrylamides including acrylamide itself and methacrylamide; the various acrylic acids including acrylic acid itself and methacrylic acid; methacrylonitrile and other copolymerizable substituted acrylonitriles; unsaturated alcohols including allyl alcohol; vinyl-substituted aromatic hydrocarbons, e.g., styrene, the various ring-substituted methylstyrenes; isopropenyl toluene; and others including those given by way of example in, for instance, Cresswell U.S. Patent No. 2,558,730, dated July 3, 1951 (column 3, lines 31-55), and Price U.S. Patent No. 2,736,722, dated February 28, 1956 (column 4, line 66, through line 27 in column 5). The third different monoethylenically unsaturated material mentioned above includes within its meaning a plurality of such materials.

Vinylpyridines which can be employed in making copolymers with acrylontrile, and used as herein described, are Vinylpyridines represented by the formula and which include 2-vinylpyridine, 3-vinylpyridine and 4-vinylpyridine; methyl Vinylpyridines represented by the formula (II) C H=C H:

and which include 2-methyl-3-vinylpyridine, 3-vinyl-4- methylpyridine, 3-vinyl-5-methylpyridine, 2-vinyl-3-methylpyridine, 2-vinyl-4-methylpyridine, 2-vinyl-5-methylpyridine, 2-vinyl-6-methylpyridine, 2-methyl-4-vinylpyridine and 3-methyl-4-vinylpyridine. The Vinylpyridines embraced by Formula II are a preferred subgroup within a broader class of Vinylpyridines that are advantageously employed in making copolymers which, in filamentary form, are used in practicing the present invention and which may be represented by the formula CH=CH7 and wherein R represents a lower alkyl radical, more particularly a methyl, ethyl, propyl (including n-propyl and isopropyl) or butyl (including n-butyl, isobutyl, see-butyl and tert.-butyl) radical. Other examples include 2-vinyl- 4,6-dimethylpyridine, the 2- and 4-vinylquinolines, 2-vinylquinolines, 2-vinyl-4,6-diethylpyridine and others embraced by the formula (IV) CH=CHg 1 M-n (HM-1 wherein R represents a lower alkyl radical, examples of which have been given herein before, and n represents an integer from 1 to 5, inclusive.

In addition to these numerous vinylpyridines, one can use other pyridine-containing vinyl compounds (which are intended to be comprehended within the scope of the term vinylpyridine as used herein). Illustrative of such additional compounds are the pyridyl acrylates disclosed in Lynn US. Patent No. 3,004,957 dated October 17, 1961.

Also, one can use blends of two or more different polymers wherein at least one of the polymers in such blend contains a vinylpyridine copolymerized with acrylonitrile as described above. Preferably such blend contains at least about 70% acrylonitrile on an overall basis, although any one polymer in such blend may contain less than such proportion of acrylonitrile.

One can substitute in the copolymers employed in making the filaments of the above examples an equivalent amount of any of the vinylpyridines, of which numerous examples have just been given, for the specific vinylpyri dine named in the individual copolymer, and then make spinning solutions from which filamentary polyacrylonitrile is produced and processed in accordance with the present invention.

Ordinarily, the molecular weight (average molecular weight) of the acrylonitrile homopolymer or copolymer is within the range of from about 30,000 to about 200,000, more particularly from about 40,000 to about 100,000, and still more particularly from about 60,000 to about 80,000, as calculated from a viscosity measurement of the said copolymer in dimethyl formamide using the Staudinger equation (reference: Houtz US. Patent No. 2,404,713, dated July 23, 1946). Acrylonitrile polymers which yield a solution having a specific viscosity at 40 C. within the range of 2 to when 1 gram of the polymer is dissolved in 100 ml. of 60% aqueous sodium thiocyanate have an average molecular weight which enables the polymer to be used as a filament-forming material and such polymers can, therefore, be used in forming the spinning solutions from which are made the gelled filaments that are further processed in accordance with the present invention.

The present invention is applicable to the processing of fibers formed by wetor dry-spinning techniques. We have found it to be especially valuable and useful for treating the so-called wet-spun polyacrylonitrile filamentary materials. The spining solutions employed are preferably those produced by dissolving the polymer in a solvent comprising a concentrated aqueous solution of a water-soluble salt which yields highly hydrated ions in an aqueous solution. Saturated or nearly saturated aqueous solutions of such salts in some cases may be used. More specific examples of such water-soluble inorganic salts are zinc chloride, calcium chloride, lithium bromide, cadmium bromide, cadmium iodide, sodium thiocyanate, zinc thiocyanate, aluminum perchlorate, calcium perchlorate, calcium nitrate, zinc nitrate, etc. As indicated hereinbefore, the preferred salt is an alkali-metal thiocyanate, specifically sodium thiocyanate. Other examples of suitable solvents are concentrated aqueous solutions of guanidine thiocyanate, the mono-(lower alkyl)-substituted guanidine thiocyanates, and the symmetrical and unsymmetrical di-(lower alkyl)-substituted guanidine thiocyanates.

Filaments spun from organic-solvent solutions of an acrylonitrile polymer, and which are wet-spun into a coagulating bath comprising water and/or glycerol, glycol or other coagulating liquid to form the gelled filamentary material, are amenable to processing in accordance with the present invention. In making such spinning solutions the organic solvent can be dimethyl formamide or any of the other organic solvents known to be solvents for homopolymers and copolymers of acrylonitrile, and especially those organic solvents which are soluble in or miscible with water,

In addition to the specific phosphates utilized in the above examples, many other bromoalkyl phosphates, and iodoalkyl phosphates may be used. Within the concept of this invention, the terms bromoalkyl phosphate and iodoalkyl phosphate may be defined as referring to compounds having the general formula;

In the above formula, R is an alkyl group, and preferably a lower alkyl group, having at least one bromine or iodine atom substituted therein. Illustrative of such alkyl groups may be mentioned methyl, ethyl, n-propyl, isopropyl, nbutyl, sec.-butyl, isobutyl, tert.-butyl, .amyl, hexyl, etc. In the above formula, R and R" each may be any desired organic radical so long as it does not interfere with the activity of the compound imparted by the bromoalkyl or iodoalkyl group R. Such permissible groups for R .and R (which may be the same as each other or different) include alkyl, aryl, aralkyl, cycloalkyl, and hete-rocyclic and modified forms thereof wherein such modifications include halides, sulfates, nitrates, ethers, esters, etc. While the nature of the R and R" groups is not critical so long as they do not adversely aifect the ability of the R group to produce the desired result, it has been found advantageous to utilize compounds wherein either R or R" or both are the same as R.

Specific examples of these phosphates which may be used are:

Tris (2,3-dibromopropyl) phosphate 2-iodoethy1 bis(2-chloroethyl) phosphate Tris-(ll, 3-dibromo-isopropyl) phosphate Tris l-bromoisopropyl) phosphate Tris-(dibromoethyl) phosphate 2-bromoethyl diphenyl phosphate 2,3-dibrom-opr0pyl dibenzyl phosphate Tris-( 1,3-diiodo-isopropyl) phosphate Tris*(1 bromo-B-chloro-isopnopyl) phosphate Tris-r(l1-chloro-3-bromoisopropyl) phosphate Tris-(tribromoneopentyD phosphate Tris-( l,2-dibromo-3-chloro-neopentyl) phosphate Tris-(I1-bromo-2,3-dichlor-o-neopentyl) phosphate Ethylene di-(dibromoethyl phosphate) It is thus seen that there is provided herein a process for modifying the dye characteristics of a certain class of polymeric materials, said class being polymeric materials of acrylonitrile containing a vinylpyridine polymerized therewith. This process comprises treating such polymeric material with an iodoalkyl phosphate or a bromoalkyl phosphate, said haloal'kyl phosphates being useful regardless of the nature of the additional substituents on the phosphate so long as such additional substituents do not interfere with the action of the iodoalkyl group or the bromoalkyl group of the phosphate. In order to be effective for eliminating the cationic dyeability of these polymeric materials, they must be heated after being treated with the iodoalkyl phosphate or the bromoalkyl phosphate. These phosphates may be applied -to the vinylpyridine-oontaining acryl'onitrile polymers at any time prior to the dyeing thereof, such as when the polymeric material is a solution in a suitable solvent, when the polymeric material is in the wet gel state after coagulation, or when the polymeric material is in the dehydrated and collapsed state.

I claim:

1. A process for substantially eliminating the dyeability by cationic dyes of polymeric materials of acrylonitrile containing a vinylpyridine polymerized therewith, said process comprising treating such polymeric material with a compound selected from the group consisting of iodoalkyl phosphates and bromoalkyl phosphates and heating the thusly-treated polymeric material.

2. A process defined in claim 1 wherein said compound is tris-(2,3-dibromopropyl) phosphate.

3. A process defined in claim 1 wherein said compound is tri-iodoethyl phosphate.

4. A process defined in claim 1 wherein said compound is di-(fi-bromoethyl)-fi-chloroethyl phosphate.

:5. A process as defined in claim 1 wherein said vinylpyridine is Z-methyI-S-Vinylpyridine.

6. A process for substantially eliminating the dyeability by cationic dyes of polymeric materials of acrylonitrile containing a vinylpyridine polymerized therewith, said process comprising treating such polymeric material with a phosphate having the formula:

wherein R is an alkyl group having at least one substituent selected from the group consisting of bromine and iodine and wherein R and R" are organic radicals which do not interfere with the activity of the R group, and heating the thusly-treated polymeric material.

7. In the process of preparing fibers from a polymeric material of acrylonitrile containing a vinylpyridine polymerized therewith by dissolving said polymeric material in a suitable solvent, extruding the thusly-formed solution into a suitable coagulating medium to form a gel structure, and collapsing said gel structure to produce a dense fiber, the improvement comprising treating such polymeric material with a compound selected from the group consisting of iodoalkyl phosphates and bromoalkyl phosphates and heating the thusly-treated polymeric material.

8. A process as defined in claim 7 wherein said compound is added to the solution of said polymeric material prior to extrusion thereof.

9. A process as defined in claim 7 wherein said compound is applied to the polymeric material while possess ing said gel structure.

10. A process as defined in claim 7 wherein said compound is applied to the polymeric material after said gel structure has collapsed.

11. In the process of preparing fibers from a polymeric material of acrylonitrile containing a vinylpyridine polymerized therewith by dissolving said polymeric material in a suitable solvent, extruding the thusly-forrned solution into a suitable coagulating medium to form a gel structure, and collapsing said gel structure to produce a dense fiber, the improvement comprising treating such polymeric material with a phosphate having the formula wherein R is an alkyl group having at least one substituent selected from the group consisting of bromine and iodine and wherein R and R are organic radicals which do not interfere with the activity of the R group, and heating the thusly-treated polymeric material.

1-2. A shaped article formed from an acrylonitrile copolymer having a polymerized vinylpyridine component and a cationic dye inhibitor consisting of a haloalkyl phosphate selected from the group consisting of iodoalkyl phosphates and bromoalkyl phosphates.

13. A shaped article in accordance with claim 12 wherein the said haloalkyl phosphate is tris-(2,3-dibromopropyl) phosphate.

14. A shaped article in accordance with claim 12 wherein the said haloalkyl phosphate is tri-iodoethyl phosphate.

15. A shaped article in accordance with claim 12 wherein the said haloalkyl phosphate is di-(fi-bromoethyl)-{3-chloroethyl phosphate.

16. A shaped article in accordance with claim 12 wherein the said vinylpyridine is 2-rnethyl-5-vinylpyridine.

17. A shaped article formed from an acrylonitrile copolymer having a polymerized vinylpyridine component and a cationic dye inhibitor consisting of a haloalkyl phosphate having the formula:

wherein R is an alkyl group having at least one substituent selected from the group consisting of bromine and iodine and wherein R and R" are organic radicals which do not interfere with the activity of the R group.

18. A textile fabric comprising two groups of fibers formed of an acrylonitrile copolyrner having a vinylpyridine component, one of said groups of fibers being modified by the addition of a cationic dye inhibitor consisting of a haloalkyl phosphate selected from the group consisting of iodoalkyl phosphates and brornoalkyl phosphates, and the second of said groups of fibers being unmodified by such dye inhibitor.

References Cited by the Examiner UNITED STATES PATENTS 1,985,771 12/1934 Eichengrun 260-306 2,773,046 12/1956 Dunn 26030.6 2,888,434 5/1959 Shashoua. 2,931,695 4/1960 Blankenship et al. 2,931,696 4/1960 Wirth et al. 2,996,474 8/1961 Voight 260-42 3,149,089 9/1964 Hayes 260-30.6

FOREIGN PATENTS 881,211 11/1961 Great Britain.

NORMAN G. TORCHIN, Primary Examiner.

JULIEN S. LEVITT, Examiner. 

1. A PROCESS FOR SUBSTANTIALLY ELIMINATING THE DYEABILITY BY CATIONIC DYES OF POLYMERIC MATERIALS OF ACRYLONIRILE CONTAINING A VINYLPYRIDINE POLYMERIZED THEREWITH SAID PROCESS COMPRISING TREATING SUCH POLYMERIC MATERIAL WITH A COMPOUND SELECTED FROM THE GROUP CONSISTING OF IODOALKYL PHOSPHATES AND BROMOALKYL PHOSPHATES AND HEATING THE THUSLY-TREATED POLYMERIC MATERIAL. 